Fan assembly

Abstract

A fan assembly includes an impeller portion generating an air flow and a motor that rotates the impeller portion about a center axis. The impeller portion is attached to a yoke of a rotor portion of the motor and is rotated with the yoke. A circular portion of the impeller is attached to a bottom opening of the yoke having a cylindrical shape whose top is covered by insert molding. Therefore, the impeller and the yoke may be securely fixed to each other. In addition, an outer side surface of the yoke is exposed to outside air such that the space arranged inward from the plurality of blades may be enlarged.

1 . A fan assembly comprising: 
 a base portion;    an armature arranged on the base portion;    a field magnet generating a torque centered about a center axis by interacting with the armature;    a yoke having a substantially cylindrical shape centered about the center axis and including an outer side surface, a closed top, and an open bottom directed toward the armature, the field magnet being accommodated inside of and fixed to the yoke;    a bearing mechanism supporting the yoke in a rotatable manner relative to the base portion; and    an impeller portion including a substantially circular portion extending radially outwardly from the open bottom or the outer side surface of the yoke, and a plurality of blades arranged around the center axis and fixed to the substantially circular portion; wherein    the substantially circular portion of the impeller portion is insert molded to the yoke; and    the impeller portion blows air from a bottom side or an upper side thereof in a direction away from the center axis.    
   
   
       2 . The fan assembly as set forth in  claim 1 , wherein a portion of the outer side surface of the yoke is exposed to an inner edge of the blades in the radial direction.  
   
   
       3 . The fan assembly as set forth in  claim 2 , wherein the substantially circular portion includes a plurality of radial affixing portions arranged around the center axis and an axial affixing portion having a surface or an edge extending in the radial direction, each radial affixing portion has a surface or an edge which constrains the radial position of the substantially circular portion against the yoke, and the axial affixing portion constrains the axial position of the circular portion against the yoke.  
   
   
       4 . The fan assembly as set forth in  claim 3 , wherein the substantially circular portion is insert molded, a plurality of weld lines extend radially on the substantially circular portion from the center axis, and each of the weld lines passes between two adjacent radial affixing portions.  
   
   
       5 . The fan assembly as set forth in  claim 3 , wherein the substantially circular portion includes a plurality of gate marks at positions radially outward from the radial affixing portions, and each gate mark is arranged substantially on an extension of a line connecting each radial affixing portion and the center axis in a plan view.  
   
   
       6 . The fan assembly as set forth in  claim 2 , wherein the yoke includes a flange portion at the open bottom, the flange portion extends in a radially outward direction, and the substantially circular portion of the impeller is fastened thereto.  
   
   
       7 . The fan assembly as set forth in  claim 2 , wherein the yoke includes a convex portion and the impeller portion includes a hole portion or a concave portion, and the convex portion is inserted into the hole portion or the concave portion so as to prevent a relative movement between the yoke and the impeller portion in the circumferential direction.  
   
   
       8 . The fan assembly as set forth in  claim 2 , wherein the yoke includes a hole portion or a concave portion and the impeller portion includes a convex portion, and the convex portion is inserted into the hole portion or the concave portion so as to prevent a relative movement between the yoke and the impeller portion in the circumferential direction.  
   
   
       9 . The fan assembly as set forth in  claim 1 , wherein the substantially circular portion of the impeller portion includes a plurality of radial affixing portions arranged around the center axis and an axial affixing portion having a surface or an edge extending in the radial direction, each radial affixing portion has a surface or an edge which constrains the radial position of the substantially circular portion against the yoke, and the axial affixing portion constrains the axial position of the circular portion against the yoke.  
   
   
       10 . The fan assembly as set forth in  claim 9 , wherein the substantially circular portion is insert molded, a plurality of weld lines extend radially on the circular portion from the center axis, and each of the weld lines passes between two adjacent radial affixing portions.  
   
   
       11 . The fan assembly as set forth in  claim 10 , wherein the yoke includes a hole portion or a concave portion and the impeller portion includes a convex portion, and the convex portion is inserted into the hole portion or the concave portion so as to prevent a relative movement between the yoke and the impeller portion in the substantially circumferential direction.  
   
   
       12 . The fan assembly as set forth in  claim 10 , wherein the yoke includes a flange portion at the open bottom, the flange portion extends in a radially outward direction, and the substantially circular portion of the impeller is fastened thereto.  
   
   
       13 . The fan assembly as set forth in  claim 12 , wherein gate marks are arranged on a portion of the substantially circular portion which axially overlaps with the flange portion.  
   
   
       14 . The fan assembly as set forth in  claim 10 , wherein the yoke includes a convex portion and the impeller portion includes a hole portion or a concave portion, and the convex portion is inserted into the hole portion or the concave portion so as to prevent a relative movement between the yoke and the impeller portion in the circumferential direction.  
   
   
       15 . The fan assembly as set forth in  claim 9 , wherein the substantially circular portion includes a plurality of gate marks at positions radially outward from those of the radial affixing portions, each gate mark is arranged substantially on an extension of a line connecting each radial affixing portion and the center axis in a plan view.  
   
   
       16 . The fan assembly as set forth in  claim 15 , wherein the yoke includes a flange portion at the open bottom, the flange portion extends in a radially outward direction, and the substantially circular portion of the impeller is fastened thereto.  
   
   
       17 . The fan assembly as set forth in  claim 16 , wherein the gate marks are arranged on a portion of the substantially circular portion which axially overlaps with the flange portion.  
   
   
       18 . The fan assembly as set forth in  claim 15 , wherein the yoke includes a hole portion or a concave portion and the impeller portion includes a convex portion, and the convex portion is inserted into the hole portion or the concave portion so as to prevent a relative movement between the yoke and the impeller portion in the circumferential direction.  
   
   
       19 . The fan assembly as set forth in  claim 15 , wherein the yoke includes a convex portion and the impeller portion includes a hole portion or a concave portion, and the convex portion is inserted into the hole portion or the concave portion so as to prevent a relative movement between the yoke and the impeller portion in the circumferential direction.  
   
   
       20 . The fan assembly as set forth in  claim 9 , wherein the yoke includes a flange portion at the open bottom, the flange portion extends in a radially outward direction, and the substantially circular portion of the impeller is fastened thereto.  
   
   
       21 . The fan assembly as set forth in  claim 1 , wherein the yoke includes a flange portion at the open bottom, the flange portion extends in a radially outward direction, and the substantially circular portion of the impeller is fastened thereto.  
   
   
       22 . The fan assembly as set forth in  claim 1 , wherein the yoke includes a hole portion or a concave portion and the impeller portion includes a convex portion, and the convex portion is inserted into the hole portion or the concave portion so as to prevent a relative movement between the yoke and the impeller portion in the circumferential direction.  
   
   
       23 . The fan assembly as set forth in  claim 1 , wherein the yoke includes a convex portion and the impeller portion includes a hole portion or a concave portion, and the convex portion is inserted into the hole portion or the concave portion so as to prevent a relative movement between the yoke and the impeller portion in the circumferential direction.